The role of hyperdipsia in aggression following septal lesions in rats

Lesions of the septum in animal subjects are known to produce an increase in aggressiveness and an increase in water intake. A series of experiments was carried out to examine the possibility that aggression was secondary to hyperdipsia. When rats with septal lesions were restricted to preoperative levels of water intake, aggression scores declined significantly. When animals without lesions were preloaded, with either water or saline, aggression increased. Neither decreased shock threshold nor increased cell hydration provided a full explanation for the results. It is suggested that the aversive nature of the stomach turgescence caused by increased water intake may be an additional mediating factor in septal aggression.